Insulated glass is heavily utilized in modern residential and commercial construction. In many areas of the country it is required by building code as an energy conservation measure. A single pane of glass alone has very little insulating value. Multi-pane insulated glass windows have much greater insulating value. Insulated glass units (IGUs) generally include two panes of glass separated by a space. Sealants and adhesives are used to bond the glass panes to a perimeter spacer which separates the two panes of glass. The entire perimeter including the two panes of glass and the spacer are sealed to one another to eliminate movement of ambient air into the space between the two panes of glass. The space is filled with dehydrated air or more commonly another gas such as argon, xenon or krypton. Sulfur hexafluoride is also used for gas filling. The filling of insulated glass units with argon or another gas that is not air has been found to increase the energy efficiency of the insulated glass units markedly. Some insulated glass units includes three panes of glass with two intervening spaces which are similarly filled with argon or another gas other than air and then edge sealed.
Current technology includes a number of techniques for filling insulated glass units with gases other than air. According to some techniques, the insulated glass unit is assembled in a chamber filled with the argon or other gas, trapping the argon between the two panes and within the spacer. In other techniques, the insulated glass unit is preassembled, the argon or other gas is injected while air is removed and then the insulated gas unit is edge sealed.
In any case, the construction of insulated glass units generally involves the use of two separate manufacturing stations, two separate processes and two separate operators to gas fill and edge seal insulated glass units plus time utilized to do the separate operations.